CARACAS, Venezuela — A police helicopter fired on Venezuela’s Supreme Court and Interior Ministry in what President Nicolas Maduro said was a thwarted terrorist attack aimed at ousting him from power. The confusing incident, which may ratchet up tensions in a country already paralyzed by months of deadly antigovernment protests, took place as Maduro was speaking live on state television Tuesday and as the high court handed down a series of rulings against the opposition. Adding to the intrigue, pictures of a blue police helicopter carrying an antigovernment banner appeared on social media around the same time as a video in which an apparent police pilot and budding action movie actor, identified as Oscar Perez, called for a rebellion against Maduro’s “tyranny.” Many of Maduro’s opponents took to social media to accuse the president of orchestrating an elaborate ruse to justify a crackdown against those seeking to block his plans to rewrite the constitution.